Grill



y@ /jj o' o I o 7, 1945',v A. l.. GREENLAW y I y 2,381,345

- GRILL Filed June'5, 1942 a' 'Mns/Nnrzmsr ma Jffz [www Patented Aeg. 7,19.45

UNIT-ED. STATES RATENT OFFl'Cl.

.fGRmL vAlfred LfG'reenlaW, New-BritainyGonm t n Application dunes,1942, serial No. .445,836

. Q3 Claims. ("Cl. 918-40) y When ,introducing airinto a room,whetherxfor heatingcooling or ventilation, .it is highly desirable. thatthis. be accomplished .in ar manner whichl will not impart xa sensationof draft :to

persons Ain `the room. -Heretofore .attempts r to avoid sensation ofdraft 'have' commonly been based 4.on the idea of reducing fthe velocityof ther air entering .the room ito .a low 4value,` and lto .this end theentering Aair column has I been enlarged in `.cross sectionf'asby theyuseofiducts flaring outwardly; toward fthe interior of the room,

in .the desired.,proportionsfbetween' the ducts. Y

The present invention'has for lanobje'ct to produce the same'freedomfrom.draftslbu't loy'a 'different method of control yw'hichihas"certainspreads outwardly. close to .thesurfacel of the'wall in which' theoutlet opening is placedanolit diffuses therefrom into the remainderofthev room.

One advantage-of this .zmethod is that it're- .quires no long/taperingair lpassages. Thus the 4grill mayjbe used where there rgisnno roomfforsuch'longair passages. For example, it is Lpossible to set the grillsubstantially flush withvthe wall,v even whenthere islittle spaceback-of-athe Wall. to. the v.end of the distribution.ductgthrough .whichthel air is suppliedk to theroom'.

A vfurther advantage ,is that. it .makes possibl j theiuse .of a grill..having exposed face' portions of substantialwidth, Which,.in turn,permits the grill `tobe made withmuchgreater mechanical strength. ,It isthus practicable 'to gplace sucha grill4 in the oor Where it maybeLwalked'onand `may support substantialweight, without iinjury.

Where no substantial .weight `is required to'rbe supported by theAgrill, it may be made of vvery light construction which can be made verycheaply and with a .small amount of material.-

The presentfapplicaton .is va continuation lin ypart of my applicationSerial No. 279,443 'filed June f16, 1939, for Grills andcontainscertain` subvject matter `.divided '..out therefrom. The-moregeneral aspects of thexinventionhare contained 1942, now Patent. No.2,341,439, February? f8, 1944,

.also as a continuation in part of my application lSerial No.279,443,1to which. reference has been made herein.

panying drawing in which yon line 2-2 vof .Figure 1.

the opposite side of the air passage. imperforate :portions .1 lie inthe same plane and .Figures 6, 'zand a are views similar to Figure' 1,but showing modifications.

Figures 9 .and 10 are detail sectional views on the correspondinglynumbered section lines of Figures 6,and 8, respectively. t

l yReferring'dirsi. to Figures 1 and 2, a grill isil--lustratedintended.for situations .where .no substantial `weight isto beborne by the grill, as,

.for example, wherefthe 'grill is placed in the Vv,ceiling 4or side wallof the room. As shown it .comprises a single plate which maybe of sheety`metal .as .at I, cut at intervals along linesgen- `erally radiatingfrom the center 2 as at 3 and then transverse to these radial lines asat lA and 5 so as to denne tongues 6 which may be de- .ected .backwardlyat an acute angle from the plane ,ofl theA sheet, therebeingformedrbetween they deected ,portions elongated imperioratelportionsywhich asshown radiate from a central imperforatewarea Stowardan imperforatemar- .ging which maybe providedwthopenings y9af to I 30ing the grillin position. VlThe deected portions receive vfasteningmeans (not shown) A for rsecur- G extend backwardly from the outer faceof the grill and leave elongated openings loforthe passage of the air,separated. by the imperorate Aportions 'L The imperforate portion 1being positioned at one v4side of each of the deflected portions 6, actseiectively therewith to define an .outer side wall-6a for the enteringair which is more Isharplyinclined to thefront face of the grill than is.the opposed inner side wall 6b formed by the orwardface of the portion6' which defines A11 of the form thefdischarge face-at the frontl of.the grill.

Theair passingthrough theopenings l0 in thismanner produces .adjacent tothe free .edge of each .of theimperforate sections 'l a suction Veffectin conjunction with a critical angle deflect vbetween the wall portions6 and 'l which tends to deflect' the air entering the room from the nextadjacent passage-directly forwardly of the delectedA portion lil "in themanner shown by thef-arrow fa" in `Figure 2. This effect is produced.lAsuccessively between adjacenty pas- :sages Iaround. the circumferenceof the grill,

this resulting in the air coming into the room escaping from the grillin directions along the front face of the wall, the air escaping fromthe outer surface of this entering air layer intol the room so graduallythat' no effect of draft is noticeable. Thus the air entering the roomdoes so at an angle to the front face of the grill much smaller than theeffective discharge angle of the grill passage which would becontrolling as to the direction of discharge in the absence of the faceof substantialwidth outwardly of each of the passages. It will be notedthat the amountl to which the cut portions are turned backwardly andtheir widths determine the entire thickness of the grill and thewidthsare determined by the spacing between the radiating lines of cut.Thus the total thickness of the grill may be reduced to a small amountby increasing the number of the cut sections. While the bending back ofthe cut sections acts to produce a slight spacing of the projection ofthe free rear edge of the sections on the plane of the front of thegrill from the adjacent side of the opening, this rear edge is so farback that the current of air efectually cuts 01T any straight passage ofair perpendicular to the front face of the grill. Such perpendicularpassage of air is torbe avoided in accordance with this invention, asthis would produce a tendency to discharge well into ie room rather thancausing the discharge to rst take place along the wall surface.

The air passing along the walls 6a and escaping at the front of thegrill produces a lower pressure effect over the front face of the nextimperforate portion l, causing the air to be discharged laterally acrossthe outer faces of these imperforate or uncut portions, rather thandirectly out into the room, as indicated by the arrow a, provided thatthe angle at which the outer walls 6a of the tongues E are disposed withrespect to the imperfor-ate portions 'I and the discharge face of thegrill is not sufcient to cause the air to break away from th outersurface of the imperforate portions.

Figures 6 to 10 illustrate constructions wherein the grill instead ofbeing madeA from sheet metal'is provided with more substantialpartitions l5 between the air passages I6, such as may be made bycasting. The rear side face I1 of eachof these'partitions has anangularity to the perpendicular to the front face of the grillcorresponding generally tothe rear face 6a. of

the deflected portion 6 of Figures 1 and 2', while the opposite sideface I8 is that' resulting from more or less filling in between the backfaces of the for-ward walls and the adjacent faces of the rearwardlydeflected portions 6 of Figure 1. precise contour of the lled in portionis of no particular consequence so long as the air is directed therebyagainst the opposite face of the slot, as will later more fully appear.Figure 6 shows a complete circular series of partitions and openings orslots, while Figures 7 and 8 show half and quarter portions,respectively, which give a less complete arc of diffusion of the air butare particularly suitable for locations where the distribution isotherwise limited as adjacent to angular wall members or near corners ofa room.

In all instances it will be noted, however, that the direction of theair discharge from the several slots is in the same direction ofrotation about the central axis or axes of the partitions. The centralportion of the grill which is shown as closed may be either round oroval as desired, Figure 8 showing a portion of a round center,

The

while Figures l, 6 and 7 sho-w the center as elliptical.

The best angles of the faces in all of the constructions shown, dependon various factors, such as width of lthe faces between the airopenings, the smoothness of the sidel faces of the air passages and thevelocity of the air entering.

Certain factors, however, have been found rather critical as follows:

(a) In a grill employing the straight slot arrangement, the length ofthe slot should be at least 6. inchesand the ratio of length to width ofthe slot should be at least 6 to l.

(b) However, in a grill employing the radial slot arrangement, theactual length of each slot is not of great importance, because the airis discharged from the grill in a fan-shaped pattern and the effectivewidth of the air stream is many times that of the actual length of theslot.

(c) The angle at the outer side of the slot in sizes of `grill-largerthan six inches diameter cannotv be much larger than 50 in order thatthe jet issuing from the slot will not break away from the contour ofthe inner wall and may be turned toward parallelism with the dischargeface of the grill, and with this angle there must be an effective borderor ilat wall margin 20 at substantially the plane of the face of thegrill, either part of the grill itself, or a wall member in a hole inwhich thegrill is set `of at least substantially two inches and three isbetter, as shown in the diagram of Figure 3. If this angle is reduced,the effective width of the border 20 may be reduced also, and with a 40angle may be substantially one inch, as shown in Fig. 4. Even with averyWide border, however, the angle cannot be safely increased more than twoor three degrees beyond 50. In this range the jet may become unstable,changing suddenly between substantial parallelism to the face of thegrill and outwardly directed at about the angle of the outer wall of theslot. This change in angle is apparently dependent on factors difficultto determine or control. With small size grills such as those of sixinches in diameter, the workable angle below the vcritical is somewhatthough not much greater than with the larger sizes. The angularity ofthe inner wall or face of the slot to the perpendicular to the face ofthe grill ap pears to be `of no particular consequence so long as ktheair jet is directed against the outer wall, butin order to so direct theair jet, its sides must either converge toward the outlet or the innerwall member must have a lip or at section near toits outer edge, or theangle of diversionfrorn the axis of the outer wall must be acute enoughto provide this pressure of the air against the outer wall. Where theouter wall does not extend to a point directly back of the inner edge eof the slot, or the forward edge of the Ainner wall 6b, thel air tendsto break away from the contour of the inner wall at a small angle. y

In Figure 5 the line is perpendicular to the outer wall member andtheline o joins the back edge of the outer iwall member with the forwardedge of the inner wall member, forming between them the angle 0. Thisangle 0 is the amount by which the discharge angle is greater than`parallel with the louter wall of the slot, line e With the radialarrangement of partitions and air passages shown herein, the airpassesinto ythe room with a whirling tendency,` the constructions of Figures'7 and 8 causing this tendency to be less than through a completerotation.

In connection with the present invention, a

question may arise in establishing the angle Cil which the inner wallofthe member or the outer .side wall of the air passage makes withrespect to the front face of the grill. For manufacturing, artistic orother reasons, it may be desirable to have either the wall or the face,or both of such design that there would not be any denite Aangle betweenthe inner wall of the air passagev and they front face of the grill, yasfor example, if the inner side walll of the air passage was concaved orconvexed, or the face of the grill was of an irregular nature. f

In designs of uns' character, in order to determine the critical anglefor the discharge of i -air through the passage, it would be necessaryto rely on experience or laboratory tests to determine the turningeffect of the particular de- Y, sign on an air stream delivered throughthe air passage. In order to limit the forward face deair streamdischarged through the opening no longer clings to the contour of thedeflected portion 6 and turns in a substantially lateral direction, but'breaks away from the contour of the y deflected portion and the uncutportion l, and

flows from the front face of the grill into the room in a more nearlyaxial direction. y From the foregoing description of certainembodimentsof thisinvention it should be evident to those skilled in theart ythatvariouschanges and modifications might be made without` departing fromthe spirit or scope of this invention.

I claim: l. A grill comprising a plate provided with a flat frontdischarge face and having a series of tongue portions struck rearwardly.therefrom f `rand defining an arcuate series of-air passages separatedby imperforate portions arranged around a central portion closed to theoutward escape of air, all of the imperforate portions lying in the sameplane and forming said front discharge face, one side face of eachtongue portion forming an outer wall for an air passage,

the other sidey face of the same tongue portion forming an inner wallfor the next adjacent air passage, the inner walls being shaped todirect lthe air passing through said passages against the outer walls,the outer walls having an angle-with respect to said discharge face ofthe grill not substantially greater than 50",'sov that the air passingthrough the passages will not break away from the inner walls andforward faces of the imperforate portions but will follow the contour ofthe inner walls kand the forward faces of said imperforate portions andbe discharged substantially laterally across the discharge face of thegrill.

2. A grill comprisingl a plate provided with a flatfront discharge faceand having a series of tongue portions struck rearwardly therefrom anddefining an arcuate series of air passages separated by imperforateportions arranged around a central portion closed to the outward escapeof air, all of the imperforate portions lying in the same plane andforming said front discharge face,one side face of each tongue portionforming an outer wall for an air passage,

the other side face of the same tongue portionforming an inner wall forthe next adjacent air passage, the inner walls being shaped to directthe airpassing through said passages against the outer walls, the outerwalls having an angle with respect to said discharge face of the grillnot less than 40 or vmore than 50, so that the air passing through thepassages will not break away from the inner walls and forward faces ofthe vimperforate portions but will follow the contour of the inner wallsand the forward faces of said imperforate portions and be dischargedsubstantially laterally across the discharge face of the grill, saidgrill having an effective substantially flat front marginal face of atleast substantially one inch in width, outwardly of said passages andimperforate portions.

3. A grill comprising a plate provided with a flat front discharge faceand having a series of tongue portions struck rearwardly therefrom anddefining a series of air passages separated by imperforate portions, allof the imperforate portions lying in the same plane and forming saidfront discharge face, said air passages being at least sixinches long,one side face of each tongue portion forming/'an outer wall for an airpassage, the other side face of the same tongue por` tion forming aninner wall for the next adjacent air passage, the inner walls beingshaped to direct the air passing through said passages against the outerwalls, the outer walls having an angle with respect to said dischargeface of the grill not substantially greater than 50, so that the airpassing through the passages will not break away from the inner wallsand forward faces of the imperforate portions but will follow thecontour of the inner walls and the front discharge faces of saidimperforate portions and be discharged substantially laterally acrossthe discharge face of the grill.

ALFRED L. GREENLAW.

